Which two of the following five physical paramenters have the same dimensions $?$
$(1) $ energy density
$(2)$ refractive index
$(3) $ dielectric constant
$(4) $ Young's modulus
$(5)$ magnetic field
Let $l, r, c$ and $v$ represent inductance, resistance, capacitance and voltage, respectively. The dimension of $\frac {l}{rcv}$ in $SI\,units$ will be